Ludwig Wittgenstein
Notes Dictated to G.E. Moore in Norway
Logical so-called propositions show [the] logical properties of language and therefore of [the] Universe, but say nothing. [Cf. 6.12.]
This means that by merely looking at them you can see these proper ties; whereas, in a proposition proper, you cannot see what is true by looking at it. [Cf. 6.113.]
It is impossible to say what these properties are, because in order to do so, you would need a language, which hadn't got the properties in question, and it is impossible that this should be a proper language. Impossible to construct [an] illogical language.
In order that you should have a language which can express or say everything that can be said, this language must have certain properties; and when this is the case, that it has them can no longer be said in that language or any language.
An illogical language would be one in which, e.g., you could put an event into a hole.
Thus a language which can express everything mirrors certain properties of the world by these properties which it must have; and logical so-called propositions shew in a systematic way those properties.
How, usually, logical propositions do shew these properties is this: We give a certain description of a kind of symbol; we find that other symbols, combined in certain ways, yield a symbol of this description; and that they do shews something about these symbols.
As a rule the description [given] in ordinary Logic is the description of a tautology; but others might shew equally well, e.g., a contradiction. [Cf. 6.1202.]
Every real proposition shows something, besides what it says, about the Universe: for, if it has no sense, it can't be used; and if it has a sense, it mirrors some logical property of the Universe.
E.g., take φa, φa ⊃ ψa, ψa. By merely looking at these three, I can see that 3 follows from 1 and 2; i.e. I can see what is called the truth of a logical proposition, namely, of [the] proposition φa . φa ⊃ ψa : ⊃ : ψa. But this is not a proposition; but by seeing that it is a tautology I can